Clarinet in A
Because it is easier to play music in flat keys on a B-flat clarinet and sharp keys on an A, orchestral players use a pair of clarinets. However, switching between them without an opportunity to warm up the instrument can cause intonation problems. These "thermoclarinets," patented by Haynes, have a double-wall construction that enables the player to quickly and silently bring the whole instrument to a uniform temperature by exhaling warm air into the cavity between the walls.
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